Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account


The faintest star visible to the naked eye has an apparent visual magnitude of about _______


How long would it take to count all the stars in the Milky Way Galaxy at a rate of one star per second?

Several thousand years

Orion is visible on winter evenings but not summer evenings because of _________

The location of the earth in its orbit

Our Sun is a star of spectral type?


The Sun's rate of fusion is gradually increasing over time


The Sun is a relatively young star, near the beginning of its life


Which of the following statements is not true?

Atmosphere of Venus is very similar to that of Earth

A major discovery made by Shapley using RR Lyrae stars and globular clusters established

The size of the galaxy and the sun's position in it

Who discovered that Jupiter has moons?


How long would it take to count all the stars in the Milky Way Galaxy at a rate of one star per second?

Several thousand years

What is the diameter of the disk of the Milky Way?

100,000 light years

Approximately how far is the Sun from the center of the galaxy?

28,000 light-years

Approximately how long does it take the Sun to orbit the Milky Way Galaxy?

230 million years

There are more large spiral galaxies than there are large elliptical galaxies


The total number of galaxies in the observable universe is estimated to be approximately

100 billion

The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about

a million years ago

The age of the universe is

Between 10 billion and 16 billion years

On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization (i.e., since ancient Egypt) existed?

A few seconds

What fraction of the mass needed to halt expansion is known to exist in the form of visible mass in the universe?

Less than 1 percent

Based on inventoried matter in the universe, including dark matter known to exist in galaxies and clusters, the actual density of the universe is what fraction of the critical density?

25 percent

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording